The invention pertains to an assembly that impinges the earth strata such as, for example, asphaltic roadway material in a road planing operation. More specifically, the invention pertains to an improved assembly that impinges the earth strata (e.g., asphaltic roadway material) in such a fashion so as to exhibit an improvement in the operational efficiency of the assembly.
Heretofore, it has been common practice to mill the surface of a roadway, and especially a roadway made of asphaltic material. Such a practice has been termed a road planing operation.
A road planing machine is used to perform the road planing operation. Exemplary patent documents that describe road planing machines include U.S. Pat. No. 6,457,779 B1 to Busley et al.; U.S. Pat. No. 6,371,566 B1 to Haehn; U.S. Pat. No. 5,505,598 to Murray; and U.S. Pat. No. 4,723,867 to Wirtgen.
A road planing machine includes a rotary road planing drum that has opposite ends and a generally cylindrical surface. The road planing drum is driven or powered by an engine whereby the drum rotates about its longitudinal axis. The surface of the road planing drum carries a plurality of blocks or holders. Each block or holder carries a road planing bit wherein the axial forward end of the bit has a hard carbide tip. Typically, the blocks or holders are arranged in a helical pattern about the surface of the road planing drum so as to, in essence, form a helical flight about the surface of the drum.
In operation, the road planing drum is rotated under the power of the engine so as to drive the hard carbide tip of the road planing bit into the asphaltic material so as break up and disintegrate the asphaltic material into smaller pieces or chunks that one can term debris. The debris is fed into a conveyor located in front of the drum and carried away from the location of the road planing activity.
The pieces or chunks (i.e., debris) located near the opposite ends of the drum may sometimes be trapped between the opposite edge of the drum and the housing of the road planing machine. In the past, in order to try to direct the debris past the opposite edges back into the helical flights of the drum, drums have exhibited edge cutter assemblies. An edge cutter assembly comprised a block with three or four bores wherein each bore contained a rotatable cutting bit. Each block has an orientation such that it extends past the opposite edge of the road planing drum so as to gather up the debris. While the use of such an edge cutter assembly has provided satisfactory results, there remains a need to provide an assembly such as, for example, a road planing assembly that exhibits improved operational efficiency. The improvement in operational efficiency can take place through an increase in the ability of the edge cutter assembly to gather and direct debris toward the helical flight.
During the road planing operation, it is not uncommon for the opposite ends of the drum, as well as the main tool holders (or blocks), to experience damage due to impingement against uncut roadway material wherein the uncut roadway material essentially defines the edge of the cutting path. Edge cutters function to cut the sides of the cutting path of the road planing drum and thereby protect the ends of the drum and the main tool holders from damage due to impingement against the uncut roadway material. Edge cutters also function to improve the quality of the cutting path by making a straighter edge in the roadway material that defines the cutting path.
Heretofore, the edge cutter assemblies have been useful to protect the opposite edges from damage. As mentioned above, the earlier edge cutter assembly comprised a block with three or four bores wherein each bore contained a rotatable cutting bit. While the use of such an edge cutter assembly has provided satisfactory results, there remains a need to provide an assembly such as, for example, a road planing assembly that exhibits improved ability to protect the opposite edges of the road planing drum. The improvement in protection can take place through an improved edge cutter assembly.
It should be appreciated that although the above discussion describes road planing machines, the present invention is also applicable to other apparatus. For example, the present invention is applicable to reclaimer (cold recycling) machines.